It comes down to who is getting hired. When there is a 'req' in the system for a job, it can be used for a domestic employee of a foreign employee. The aim of this administration is to make the choice for a domestic employee a necessity of law. The whole visa thing is a side issue.

There is a pool of talent abroad that historically US multinationals etc. have liked to tap into. Google, Facebook, Apple and non-tech companies like the big US banks etc. tend to have sites all over the world, sometimes with thousands of employees in some offices. Its possible this latest policy will shift some roles to non-US sites if that is the best way to get the right person who happens to be a "foreigner" in the right job. It might be nice to be at the Silicon Valley or NYC office to do a particular job, but these days its by no means essential to be. If Goldman Sachs really wants to hire a European/Russian/Chinese PhD for a quant role, they will just locate them in London rather than New York (or perhaps Frankfurt now if rumours about Goldman Sachs workforce in London are to be believed).

To give extreme examples - didn't Linus Torvalds go over to the US to work at Transmeta originally (possibly on a green card instead of a visa)? If a company specifically wants Linus Torvalds from Finland working for them, then they want Linus Torvalds from Finland. Or look at when RedHat and Intel wanted to hire Alan Cox, but he didn't want to work in the US. They still hired him, but he worked from the UK. The approach of attempting to discourage or even stop companies hiring non-US nationals for tech positions currently(!) based in the US seems a little impulsive and poorly conceived to me.

It's a complicated area. I think most people in the US, including Trump voters, have little or no problem with H-1B visas, provided that they are used as intended, i.e. to attract rare, specialized talent at compensation rates that reflect the rare and specialized nature of the talent. No one has a problem with using an H-1B to hire a Linus Torvalds. Unfortunately, it's also pretty clear that a lot of companies abuse the practice to hire people with fairly common technical skills at compensation levels that are significantly below what is otherwise common in the local marketplace, in defiance of the existing laws and regulations.

That said, it's a complicated, multi-variate problem, and it's easy to create unintended consequences in many directions. Put too many restrictions on H-1Bs, and it incentivizes moving an entire department out of the country, or outsourcing entirely, rather than recruiting temporary workers to work in the US. Enforce restrictions too lightly, and you risk gutting the local workforce. Personally, I'm a free market, libertarian kind of guy, and I love working with H-1B visa holders who have world class talent (I've been fortunate to work with many in my career), so I'm biased towards a relatively open H-1B approach. At the same time, I've encountered an awful lot of H-1B workers with skills that barely qualify as mediocre who seem to be doing the same jobs as local (translation: "older" and/or "more expensive") people the employer recently laid off. In my own area of specialization, it's been especially galling to see companies complaining about "STEM talent shortages" not long after they've laid off STEM talent by the hundreds or thousands.

What is the fair and decent thing to do for everyone involved? I won't pretend to know the answer to the general problem, and I'm not going to take a harsh view of people who have views different from mine.